| 摘要 |
PURPOSE:To eliminate such a malfunction as a focus is pulled in on the surface of a protective layer by locking a focus once on the surface of a disk protective layer, and subsequently, closing a focus-servo by setting a longer time than the time required for locking on the surface of the protective layer, at the time of succeedingly executing a pull-in operation. CONSTITUTION:After having detected a light beam reflecting signal from the surface of a disk protective layer, which is generated at the time of pulling in a focus, a focus servo is closed, and locked to the surface of the protective layer once. Thereafter, the focus servo is opened, and subsequently, a focus pull-in operation is repeated. At the time of this repeated operation, the timing for closing the focus servo is set longer than the time required for locking to the surface of the protective layer. In such a way, after a reflecting signal from the surface of the protective layer is detected completely, the focus servo is closed, therefore, the focus servo is not pulled in on the surface of the disk protective layer, but can be exactly pulled in the recording film.
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